Creavalle put the Canadians ahead on 20 minutes with a scuffed finish into the bottom corner from the left edge of the box.
Former Aston Villa and West Bromwich Albion striker Luke Moore blazed over the crossbar for Toronto moments later, before Montreal began to apply some pressure at the other end.
The visitors to BMO Field took this momentum into the second period as McInerney hit the crossbar, while Martins and Pearce also had chances as Toronto goalkeeper Joe Bendik kept them on level terms.
Gilberto spurned an opportunity at the other end and shot straight at Impact stopper Evan Bush before the game's feisty final stages, which saw Pearce dismissed for a reckless 82nd-minute lunge on Dominic Oduro.
The referee evened things up in stoppage time as Toronto's Jonathan Osorio was shown red on a bad night for his side, who are now five points behind Columbus Crew with one regular-season game left to play.
Montreal's Hassoun Camara was shown a second booking for his part in a post-game melee.